This invention relates to the art of electromagnetically operated fluid pumps, and more particularly to a new and improved electromagnetic pump which operates at extremely low power.
One area of use of the present invention is implantable drug delivery systems, although the principles of the present invention can be variously applied. The principal requirements for a pump in such applications are low power drain, since the pump must be driven by an implanted battery, and compatibility with the drug being pumped. Additional important requirements are that the pump have a simplified structure and method of assembly while at the same time having improved performance, that the pump operates in a manner preventing damage to fragile drugs such as insulin, that moving parts of the pump be resistant to wear and that the stroke volume of the pump be adjustable within a relatively short time.
It would, therefore, be highly desirable to provide an electromagnetically operated pump which is safe, reliable, small in size, light in weight, which operates without excessive demand on the available energy supply, which is compatible with drugs or similar liquids to be pumped, which has a relatively simple structure and method of assembly while at the same time having improved performance, which operates in a manner preventing damage to fragile drugs such as insulin, which has wear resistant movable parts and which has a relatively quickly adjustable stroke volume.
It is, therefore, a primary object of this invention to provide a new and improved electromagnetically operated pump.
It is a more particular object of this invention to provide such a pump which operates at extremely low power levels.
It is a further object of this invention to provide such a pump which is compatible with the fluid being pumped.
It is further object of this invention to provide such a pump which is electronically and magnetically efficient.
It is a further object of this invention to provide such a pump which operates in a manner preventing damage to fragile liquids such as insulin.
It is a further object of this invention to provide such a pump wherein the stroke volume is adjustable within a relatively short period of time.
It is a further object of this invention to provide such a pump wherein the moving parts are resistant to wear;
It is a further object of this invention to provide such a pump which has a relatively simple structure and method of assembly.
The present invention provides an electromagnetic pump comprising a housing having an interior fluid containing region including a fluid receiving chamber in communication with an inlet, a fluid output chamber in fluid communication with an outlet, check valve means operatively associated with the fluid containing region for allowing fluid flow in a direction from the inlet toward the outlet and blocking fluid flow in a direction from the outlet to the inlet, electromagnet means carried by the housing located external to the fluid containing region, and barrier means of fluid impervious material for isolating the electromagnet means from the fluid chambers. An armature movable in the housing has a pole portion located for magnetic attraction by the electromagnet means and has a plunger portion extending from the pole portion, the armature being movably supported in the housing for movement from a rest position through a forward pumping stroke when attracted by the electromagnet to force fluid from the output chamber through the outlet and for movement in an opposite direction through a return stroke back to the rest position. There also is provided means defining a magnetic circuit including the electromagnet means, the armature and a gap between the armature pole portion and the electromagnet means for moving the armature toward the electromagnet means to close the gap in response to electrical energization of the electromagnet means.
The foregoing and additional advantages and characterizing features of the present invention will become clearly apparent upon a reading of the ensuing detailed description together with the included drawing wherein: